There are still some programs that have executable stack regions, which results in their being vulnerable to exploitation via stack memory. There are only a few very rare situations where executable stacks are actually desired, the rest are usually the result of lacking flags in assembly code or using nested functions (which are generally avoidable).

• Detection:

  • check an ELF binary: "readelf -lW $BIN | grep GNU_STACK" shows with "E" flag.
  • check a .o file: "scanelf -qe $BIN" shows with "X" flag.

• Information: Gentoo write-up about exec stack handling: http://www.gentoo.org/proj/en/hardened/gnu-stack.xml

• Potential Solutions:

  • fix assembly source by adding flags to assembler: .section        .note.GNU-stack, "", @progbits

  • fix compiler's default when encountering unmarked assembly: -Wl,-z,noexecstack will change the behavior of compiler's asm-without-stack-markings defaults.

  • rework code to avoid using nested functions.
  • force markings into a safe state via "execstack -c $BINARY" during package build.

Main/Restricted Packages

Originally generated from the ELF files with executable stacks in Karmic main.

Fixed

• zip

• bogl

• mono

Nested Functions

Uses Nested Functions which compiler generates as trampolines on the stack.

• grub

• grub2 upstream bug

Trampolines

• klibc (setjmp implementation)
• kexec-tools (statically linked against klibc)

Shipped Precompiled Binary

• fglrx-installer

• nvidia

  • nvidia-graphics-drivers-173
  • nvidia-graphics-drivers-180
  • nvidia-graphics-drivers-71
  • nvidia-graphics-drivers-96

Unmarked Assembler

• openjdk-6

Unclassified

• icon
• john
• link-grammar
• mbr
• memtest86+

Fedora Patches

• http://cvs.fedoraproject.org/viewcvs/devel/gdk-pixbuf/gtk+-2.2.2-noexecstack.patch?view=markup

• http://cvs.fedoraproject.org/viewcvs/devel/libdv/libdv-0.104-no-exec-stack.patch?view=markup

• http://cvs.fedoraproject.org/viewcvs/devel/lightning/lightning-1.2-execstack.patch?view=markup

• http://cvs.fedoraproject.org/viewcvs/devel/ocaml/ocaml-3.11-dev12-no-executable-stack.patch?view=markup

• http://cvs.fedoraproject.org/viewcvs/devel/qimageblitz/qimageblitz-0.0.4-noexecstack.patch?view=markup

• http://cvs.fedoraproject.org/viewcvs/devel/mlton/mlton-20070826-no-execmem.patch?view=markup